Method for reducing crosstalk in electrical connectors

ABSTRACT

An apparatus and method for crosstalk compensation in a jack of a modular communications connector includes a flexible printed circuit board connected to jack contacts and to connections to a network cable. The flexible printed circuit board includes conductive traces arranged as one or more couplings to provide crosstalk compensation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/833,686, filed Aug. 3, 2007, which is a continuation of U.S. patentapplication Ser. No. 11/078,816 filed Mar. 11, 2005, which claims thebenefit of U.S. Provisional Application No. 60/558,657, filed Apr. 1,2004; and U.S. Provisional Application No. 60/552,995, filed Mar. 12,2004, which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to electrical connectors and moreparticularly relates to modular communication connectors that utilizecompensation techniques to reduce net crosstalk generated by thecombination of a plug and a jack of a connector assembly.

BACKGROUND

Computer networks, including local area networks (LANs) and wide areanetworks (WANs), are becoming increasingly prevalent as the number ofcomputers and network devices in the workplace grows. These computernetworks utilize data communication cables and electrical connectors totransmit information between various components attached to the network.The electrical connectors are typically configured to include a plugthat is connectable to a jack mounted in the wall, or integrated into apanel or other telecommunication equipment. The jack typically includesa housing that holds an array of closely spaced parallel contacts forcontacting corresponding conductors of the plug. The contacts of a jackare often mounted onto a printed circuit board. An RJ45 plug and jackconnector assembly is one well-known standard connector assembly havingclosely spaced contacts.

Over the past several years, advances in computer networking technologyhave facilitated a corresponding increase in the rate at which data canbe transmitted through a network. Conventional connectors have been usedto transmit low-frequency data signals without any significant crosstalkproblems. However, when such connectors are used to transmithigh-frequency data signals, crosstalk generated within the connectorincreases dramatically. This crosstalk is primarily due to thecapacitive and inductive couplings between the closely spaced parallelconductors within the jack and/or the plug.

A wide variety of improvements have been made in the design ofelectrical connectors to reduce crosstalk occurring within connectors.One example is disclosed in U.S. Pat. No. 6,305,950, which is commonlyassigned to Panduit Corporation. This type of connector uses aparticular conductor configuration in conjunction with a multi-layeredprinted circuit board containing capacitors to achieve a reduction inthe crosstalk effect. However, due to the high level of crosstalkoccurring in the plug for this connector at very high-frequency signalrates, the tuning effect achievable by the capacitors can still bedifficult to accomplish. As such, further improvements in the design ofconnectors are still needed to address such problems and provideimproved crosstalk performance.

SUMMARY OF THE INVENTION

According to one embodiment of the present invention, a communicationsconnector utilizes a flexible printed circuit to provide crosstalkcompensation. The flexible printed circuit is in electrical contact withcontacts of the communications connector.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is an exploded view of an electrical jack according to oneembodiment of the present invention;

FIG. 2 is an exploded view of a contact assembly showing the use of aflexible printed circuit;

FIG. 3 is a rear perspective view of the contact assembly of FIG. 2;

FIG. 4 is a side cutaway view of the electrical jack of FIG. 1;

FIG. 5 is a side cutaway view of an electrical jack according to analternative embodiment of the present invention;

FIG. 6 is a plan view of a flexible printed circuit showing zones A-F;

FIG. 6 a is a detail view of Zone A of the flexible printed circuit ofFIG. 6;

FIG. 6 b is a detail view of Zone B of the flexible printed circuit ofFIG. 6;

FIG. 6 c is a detail view of Zone C of the flexible printed circuit ofFIG. 6;

FIG. 6 d is a detail view of Zone D of the flexible printed circuit ofFIG. 6;

FIG. 6 e is a detail view of Zone E of the flexible printed circuit ofFIG. 6;

FIG. 6 f is a detail view of Zone F of the flexible printed circuit ofFIG. 6;

FIG. 6 g is a plan view of the flexible printed circuit of FIG. 6, withsectional lines;

FIG. 6 h is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a first conductor;

FIG. 6 i is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a second conductor;

FIG. 6 j is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a third conductor;

FIG. 6 k is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a fourth conductor;

FIG. 6 l is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a fifth conductor;

FIG. 6 m is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a sixth conductor;

FIG. 6 n is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with a seventh conductor;

FIG. 6 o is a plan view of the flexible printed circuit of FIG. 6showing a conductive trace associated with an eighth conductor;

FIG. 7 is a sectional view of the flexible printed circuit of FIG. 6taken along the line A-A of FIG. 6 g;

FIG. 8 a is a sectional view of the flexible printed circuit of FIG. 6taken along the line B-B of FIG. 6 g;

FIG. 8 b is a sectional view of the flexible printed circuit of FIG. 6taken along the line C-C of FIG. 6 g;

FIG. 9 is a sectional view of the flexible printed circuit of FIG. 6taken along the line D-D of FIG. 6 g;

FIG. 10 a is a sectional view of the flexible printed circuit of FIG. 6taken along the line E-E of FIG. 6 g;

FIG. 10 b is a sectional view of the flexible printed circuit of FIG. 6taken along the line F-F of FIG. 6 g;

FIG. 11 is a sectional view of the flexible printed circuit of FIG. 6taken along the line G-G of FIG. 6 g;

FIG. 12 is a sectional view of the flexible printed circuit of FIG. 6taken along the line H-H of FIG. 6 g;

FIG. 13 is a sectional view of the flexible printed circuit of FIG. 6taken along the line I-I of FIG. 6 g;

FIG. 14 is a detail view of the detail J of FIG. 6 g;

FIG. 15 is a detail view of the detail K of FIG. 6 g;

FIG. 16 is a detail view of the detail L of FIG. 6 g;

FIG. 17 is a detail view of the detail M of FIG. 6 g;

FIG. 18 is a side cutaway view of an electrical jack according toanother alternative embodiment of the present invention;

FIG. 19 is an exploded view of the electrical jack of FIG. 18;

FIG. 20 is a detail view of the detail N of FIG. 19;

FIG. 21 is a perspective view of a contact-and-housing assembly of theelectrical jack of FIG. 18;

FIG. 21 a is a perspective view of an alternate embodiment of acontact-and-housing assembly of the electrical jack of FIG. 18;

FIG. 22 is a perspective view of the contact-and-housing assembly of theelectrical jack of FIG. 18;

FIG. 23 is a perspective view of IDCs and associated stems according toone embodiment of the present invention;

FIG. 24 is a top view of IDCs of FIG. 23;

FIG. 25 is a front view of the IDCs of FIG. 23;

FIG. 26 is a rear view of the IDCs of FIG. 23;

FIG. 27 is a side view of the IDCs of FIG. 23;

FIG. 28 is a detail view of the detail O of FIG. 27;

FIG. 29 is a detail view of the detail P of FIG. 27;

FIG. 30 is a sectional view taken along the line Q-Q of FIG. 27;

FIG. 31 is a plan view of an alternative FPC 200, which may be used withthe jack shown in FIGS. 33-45;

FIG. 32 is a perspective view of the variable capacitance 250 shown inFIG. 31;

FIG. 33 is a side cutaway view of the front portion of a jack, showingcontact 1 or 8 in a combed position;

FIG. 34 is a side cutaway view of the front portion of a jack, showingcontact 1 or 8 in a solid-plug position;

FIG. 35 is a side cutaway view of the front portion of a jack, showingcontacts 2, 4, 5, or 7 in a combed position;

FIG. 36 is an upper right-hand front exploded perspective view of a jackin accordance with an embodiment of the present invention;

FIG. 37 is a close-up view showing detail of the front sled withcontacts, including spring contacts;

FIG. 38 is a close-up view showing detail of the rear contact guides;

FIG. 39 is a lower left-hand rear exploded perspective view of a jack inaccordance with an embodiment of the present invention;

FIG. 40 is a close-up view showing detail of the bottom of the frontsled with contacts, including spring contacts;

FIG. 41 is a first rear perspective view of the housing of a jack inaccordance with an embodiment of the present invention;

FIG. 42 is a second rear perspective view of the housing of a jack inaccordance with an embodiment of the present invention;

FIG. 43 is a perspective view of the contacts, including springcontacts;

FIG. 44 is a perspective view of a long contact; and

FIG. 45 is a perspective view of a short contact.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is directed to methods and apparatus for reducingcrosstalk in electrical connectors. The present invention utilizescrosstalk-reduction principles of U.S. Pat. No. 5,997,358 toAdriaenssens et al., which is incorporated herein by reference in itsentirety. The present application further incorporates by reference inits entirety commonly-assigned U.S. Provisional Patent Application No.60/544,050 entitled “Methods and Apparatus for Reducing Crosstalk inElectrical Connectors,” filed Feb. 12, 2004, and commonly-assigned U.S.patent application Ser. No. 11/055,344, entitled “Methods and Apparatusfor Reducing Crosstalk in Electrical Connectors,” filed Feb. 10, 2005.

Turning now to FIG. 1, an exploded view of an electrical jack 10 isshown. Contacts 12 are adapted to make physical and electrical contactwith contacts of a plug (not shown in FIG. 1) and further to makeelectrical contact with a flexible printed circuit (FPC) 14. Thecontacts 12 are mechanically mounted in a contact sled 16 and thecontact-and-sled assembly is adapted for insertion into a main jackhousing 18.

In the embodiment shown in FIG. 1, the FPC 14 has a rigid extension 20adapted for accepting insulation displacement connectors (IDCs) 22.According to one embodiment of the present invention, the rigidextension 20 is an integral end portion of the FPC. The IDCs 22 extendthrough a rear housing 24 and make physical and electrical contact withconductors 26. In the embodiment of FIG. 1, eight conductors 26 areprovided in four pairs. A termination cap 28 encloses the connectionsbetween the IDCs 22 and the conductors 26. Other styles of terminations,such as punch-down style terminations, may also be used with the presentinvention.

Turning now to FIG. 2, an exploded view of a contact assembly shows theconnection between the contacts 12 and the FPC 14 at jack contact points30 of the FPC 14. The mechanical and electrical connection between theFPC 14 and the contacts 12 is directly under the plug/jack interface 31.The jack contact points 30 of the FPC 14 are preferably attached to thecontacts 12 opposite a plug/jack interface by electrical resistancewelding of solder rivets. The jack contacts 12 are relatively short andthey do not conduct signal current down their length. The IDCs 22 extendthrough the rigid extension 20 of the FPC 14 into IDC sockets 32 of theFPC 14. FIG. 3 is a back perspective view of the contact assembly ofFIG. 2 showing the jack contact points 30 of the FPC contacting thecontacts 12 and further showing the IDCs 22 extending from the rigidextension 20 of the FPC 14.

FPCs according to the present invention may be positioned in a varietyof ways. For example, FIGS. 4 and 5 are side cutaway views showing twoconfigurations of an FPC 14 in electrical jacks. In FIG. 4, the FPC 14is placed such that the jack contact points 30 of the FPC 14 bend towardthe rear of the electrical jack 10. This is the configuration shown inFIG. 1. FIG. 5 shows an alternative configuration in which a forwardbend 34 is provided in the FPC 14 such that the jack contact points 30bend toward the front of the alternative electrical jack 36. In FIGS. 4and 5, the jack contact points 30 of the FPC 14 contact the contacts 12of the jacks directly under the plug/jack interface 31.

Turning now to FIG. 6, a plan view of an FPC 114 according to oneembodiment of the present invention is shown. Jack contact points 130include solder rivets 131 for electrical resistance welding to jackcontacts. The jack contact points 130 are numbered one through eight tocorrespond to eight conductors (provided in four pairs), and IDC sockets132 are numbered correspondingly. Conductive traces 138 are provided onthe FPC 114. The FPC 114 is adapted for use in a “horizontal extension”embodiment of a jack as shown in FIGS. 18-22.

The FPC 114 electrically connects each jack contact to an IDC and itprovides compensation for the crosstalk couplings of a specificationplug. It utilizes the teachings of U.S. Pat. No. 5,997,358 to providesaid compensation. The FPC 114 is divided into zones as shown in FIG. 6.

The critical pair compensation is for conductor pairs 3,6 to 4,5 asshown in FIG. 6. The zone descriptions below pertain to these pairs andthe following statements regarding couplings pertain to couplingsbetween these pairs. The regions of Zones A, B, C, D, E, and F are shownin FIG. 6 with dotted boxes and plan views of the conductive traces inZones A-F are shown in FIGS. 6 a-6 f, respectively.

Zone A is a transition zone from the connection to the jack contacts 112(shown in FIG. 18) to the near-end crosstalk (NEXT) compensation zone.

Zone B is the NEXT compensation zone.

Zone C is a transition zone from the NEXT compensation zone to the NEXTcrosstalk zone. The design objectives of this zone are to make itsinductive and capacitive couplings and the length of the circuit pathsequal to those of Zone A.

Zone E is the NEXT crosstalk zone.

Zone F is a neutral zone which connects the NEXT crosstalk zone to theIDC sockets 32.

The magnitude of the total crosstalk coupling of the NEXT crosstalk zoneis approximately equal to that of a specification plug.

The magnitude of the total compensation coupling of the NEXTcompensation zone is slightly less than twice the crosstalk coupling ofa specification plug plus twice the total coupling of Zone A.

All the above Zones A-C, E, and F have distributed couplings and noremote couplings.

The phase angle change between the effective center of couplings of aspecification plug and the center of the NEXT compensation zone isapproximately equal to the phase angle change between the center of theNEXT crosstalk zone and the NEXT compensation zone.

The combination of the jack and a specification plug is thereforesymmetrical about the center of the NEXT compensation zone.

The result of the above is that Forward NEXT is equal to Reverse NEXT.

Since the NEXT compensation zone is connected to the plug/jack interfaceby short circuit paths in the FPC, the phase angle change between themis minimized and the change in compensation vs. frequency is minimized.

The total inductive coupling of the NEXT compensation zone isapproximately equal to the total inductive couplings of the balance ofthe circuit path of the jack and a specification plug. The result is avery low FEXT.

The flexibility of the FPC allows it to be connected to all the jackcontacts which do not move exactly in unison when a plug is installed.It also facilitates connection to various orientations of IDCs or to aprinted circuit board (PCB). The relatively thin dielectric layer of theFPC as compared to that of a PCB facilitates a high density of inductiveand capacitive couplings which facilitates a relatively short NEXTcompensation zone.

The length of the NEXT compensation zone is preferably approximatelyequal to the length of the NEXT crosstalk zone. The result is thatvariations in FPC trace width, which tend to be consistent on anindividual FPC, change the capacitive coupling of the NEXT compensationzone and the NEXT crosstalk zone by approximately the same magnitude.This minimizes the compensation variation due to trace width variation.

Zone D is a compensation zone to compensate for the jack contacts. Itprovides remote capacitive coupling which is connected close to theplug/jack interface.

The circuit paths for pairs 1,2 & 7,8 as shown in FIG. 6 illustrate oneway in which compensation between these pair combinations can beattained. The required compensation for these other pairs is much moreeasily attained than that for pairs 3,6 to 4,5.

FIGS. 6 h-6 o respectively show conductive traces associated withconductors 1-8, with traces on an upper level of the FPC 114 shown insolid lines and traces on a lower level of the FPC 114 shown in dashedlines. Vias 117 are conductive routes from the upper level to the lowerlevel of the FPC 114. The lengths of conductive traces for pairs 3, 6and 4, 5 are approximately equal.

Turning now to FIG. 7, a cross-sectional view along the line A-A of FIG.6 g, shows cross-sections of the jack contact points 130 of the FPC 114.Similarly, FIG. 8 a is a cross-sectional view along the line B-B of FIG.6 g. FIG. 8 b is a cross-sectional view along the line C-C of FIG. 6 g.

FIG. 9 is a cross-sectional view along the line D-D of FIG. 6 g.

FIG. 10 a is a cross-sectional view along the line E-E of FIG. 6 g.

FIG. 10 b is a cross-sectional view along the line F-F of FIG. 6 g.

FIG. 11 is a cross-sectional view along the line G-G of FIG. 6 g.

FIG. 12 is a cross-sectional view along the line H-H of FIG. 6 g.

FIG. 13 is a cross-sectional view along the line I-I of FIG. 6 g.

The numbers one through eight associated with the conductive traces inFIGS. 7-13 show that the referenced conductive traces correspond to thejack contact points 130 of the FPC 114 and, in turn, with thecorresponding conductors to which the jack is connected.

FIGS. 14-17 are, respectively, detail views of detail areas J, K, L, andM of FIG. 6 g. Dimensions shown in FIGS. 6 g and 7-17 are in inches andare provided for illustration of one particular embodiment of thepresent invention. It is to be understood that embodiments havingdifferent dimensions are contemplated as falling within the scope of thepresent invention.

Turning now to FIG. 18, a cross-sectional view of a jack 110 having ahorizontal extension 120 of the FPC 114 is shown. As with the embodimentof FIG. 1, the contacts 112 make electrical and mechanical contact withthe FPC 114 and the plug-jack interface 131 is disposed directly abovethe contact between the contacts 112 and the FPC 114. IDCs 122 areinserted into IDC sockets of the horizontal extension 120 of the FPC114. Other styles of terminations, such as punch-down terminations, mayalso be used with the present invention.

FIG. 19 is an exploded view of the jack 110. A main jack housing 118 isadapted to hold a sled 116 with contacts 112 mounted therein. An IDCblock assembly 115 is attached to a rear housing 124 and a terminationcap 128 is provided at the rear of the jack 110. The extension 120 ofthe FPC 114 is disposed horizontally to accept IDCs 122. FIG. 20 is adetail view of the detail N of FIG. 19 showing the FPC 114 makingelectrical and mechanical contact with the contacts 112 and furthershowing IDC sockets 132 adapted to connect to IDCs 122.

FIGS. 21, 21 a, and 22 are perspective views showing the housing 124,the IDC block assembly 115, the contacts 112, and the FPC 114 with itshorizontally-oriented rigid extension 120. In an alternative embodiment,as shown in FIG. 21 a, one or more pairs of IDCs 122 may be providedwith crossover stems 123 in the IDC block assembly 115.

According to one embodiment of the present invention, illustrated inFIG. 23, IDCs 122 are provided with stems 134, with some stems 134incorporating crossovers 136. FIG. 23 is a perspective view showing IDCs122 a-h corresponding, respectively, to first through eighth conductorsof a jack. First through eighth stems 134 a-h correspond respectively tofirst through eighth IDCs 122 a-h. First and second stems 134 a and 134b cross over each other at a first crossover 136 a, and fourth and fifthstems 134 d and 134 e cross over each other at a second crossover 136 b.

FIG. 24 is a top view of the first, second, seventh, and eighth IDCs 122a, 122 b, 122 g and 122 h showing the first crossover 136 a in the firstand second stems 134 a and 134 b.

FIG. 25 is a front view of the IDCs 122 a-h and their associated stems134 a-h showing first and second crossovers 136 a and 136 b. FIG. 26 isa rear view of the IDCs 122 a-h showing the features of FIG. 25.

FIG. 27 is a side view of the embodiment of FIG. 23 showing IDCs andassociated stems. The first crossover 136 a between first and secondstems 134 a and 134 b is shown. FIG. 28 is a view of the detail O ofFIG. 27 showing the first crossover 136 a. FIG. 29 is a view of thedetail P of FIG. 27 showing the third and sixth stems 134 c and 134 f.FIG. 30 is a sectional view of the section Q-Q of FIG. 27, showingthird, fourth, fifth, and sixth IDCs 122 c-f with their associated stems134 c-f and further showing the second crossover 136 b between thefourth and fifth stems 134 d and 134 e. Sections of the first, second,seventh, and eighth stems 134 a, 134 b, 134 g, and 134 h are also shownin FIG. 30.

FIG. 31 is a plan view of an alternative FPC 200, which may be used withthe jack shown in FIGS. 33-45. Jack contact points 230 include vias(plated through holes) 231 for electrical connection to jack contacts.The jack contact points 230 correspond to eight conductors (provided infour pairs). Only four (conductors 3, 4, 5, and 6) are shown in FIG. 31.Conductive traces 238 are provided on the FPC 200. The FPC 200 isadapted for use in a “vertical extension” embodiment of a jack as shownin FIGS. 33-45.

The FPC 200 electrically connects each jack contact to an IDC and itprovides compensation for the crosstalk couplings of a specificationplug. It utilizes the teachings of U.S. Pat. No. 5,997,358 to providesaid compensation. The FPC 200 is divided into zones as shown in FIG.31.

The critical pair compensation is for conductor pairs 3,6 to 4,5 asshown in FIG. 31. The zone descriptions below pertain to these pairs andthe following statements regarding couplings pertain to couplingsbetween these pairs. The regions of Zones A, B, C, D, and E are shown inFIG. 31. These Zones are identified below, but the functions aredescribed above, with reference to FIGS. 6-17.

Zone A is a transition zone from the connection to the jack contacts tothe near-end crosstalk (NEXT) compensation zone.

Zone B is the NEXT compensation zone. As illustrated, it includes anoptional variable capacitance 250 (described below, with reference toFIG. 32).

Zone C is a transition zone from the NEXT compensation zone to the NEXTcrosstalk zone. The design objectives of this zone are to make itsinductive and capacitive couplings and the length of the circuit pathsequal to those of Zone A.

Zone E is the NEXT crosstalk zone.

The traces below Zone E in FIG. 31 make up a neutral zone that connectsthe NEXT crosstalk zone (Zone E) to the IDC sockets.

FIG. 32 is a perspective view of the variable capacitance 250 shown inFIG. 31. The variable capacitance 250 provides a capacitive couplingthat effectively decreases as frequency increases. FIG. 32 is an upperperspective view of this portion showing the capacitive plates, with thesubstrate removed for ease of illustration. In general, the distributedcoupling of the compensation zone would be reduced by the magnitude ofcapacitive change of the remote coupling of variable capacitance 250.The technology of the variable capacitive coupling is described in U.S.patent application Ser. No. 60/559,846, entitled “Electrical Connectorwith Improved Crosstalk. Compensation,” filed on Apr. 6, 2004 andincorporated herein by reference in its entirety.

FIGS. 33-45 are various views of an illustrative embodiment of thepresent invention, in which alternating-length contacts include integralspring clips for connecting to a flexible printed circuit (FPC). FIGS.33-35 are side cutaway views of a portion of such a jack. FIGS. 36 and39 are exploded perspective views of a complete jack. FIGS. 37, 38, and40-42 are detailed perspective views of components of the jack. FIGS.43-45 show details of the jack contacts (also known as plug interfacecontacts).

The jack 300 includes a housing 302 that includes an integral front comb304 and “sandwich-style” contact mounts 306 to hold and position aplurality of contacts 308. The front comb 304 limits the upward travelof the contacts 308. Each of the contacts 308 has a corresponding rearcontact guide 310 into which the contacts 308 may travel upon insertionof a plug (not shown) into the jack 300. A FPC 312 is electrically andmechanically connected at one end to a printed circuit board (PCB) 314,which further connects to IDCs 316 that connect to a network cable (notshown). A second end of the FPC 312 is connected to the contacts 308 bya plurality of spring contacts 318. Each of the spring contacts 318 ispreferably s-shaped to securely hold the FPC 312 so that a goodelectrical connection is maintained between the contacts 308 and the FPC312. The jack further includes a bottom mounting plate 320 for mountinga front sled (around which contacts 308 are placed) in the housing 302.A rear sled 324 mechanically connects the housing (and components housedtherein) to a wire cap 326 designed to accept a network cable forplacement of individual wires (not shown) in the IDCs 316. In theparticular wire cap 326 shown, a strain relief clip 328 securely holdsthe network cable in place, lessening strain on the individual wireswithin the network cable. The particular arrangement of the rear sled324, wire cap 326, and strain relief clip 328 is shown as an exampleonly. Many other designs could also be used, including those for apunch-down jack.

An advantageous feature of the jack 300 described with reference toFIGS. 33-45 is the use of contacts 308 having alternating lengths. Asshown in FIGS. 43-45, half of the contacts 308 a are longer in lengththan the other half 308 b. While the spring contacts 318 on each contact308 are aligned with one another, the lower portions that wrap aroundthe front sled 322 for mounting in the contact mounts 306 substantiallyalternate from one end of the front sled 322 to the other. The middletwo contacts 308 are the only two neighboring contacts 308 that have thesame length, in the preferred embodiment. The difference in lengthbetween neighboring contacts 308 a and 308 b results in the contacts 308a and 308 b being situated at different locations in relation to oneanother. This, in turn, reduces the capacitive couplings between contactpairs, which reduces crosstalk. To accommodate the different contacts308 a and 308 b, the front comb 304 and front sled 322 are designed forboth lengths of contacts.

Another feature of the design of contacts 308 is that thosecorresponding to wires 1 and 8 (the outside contacts) are both of thelonger length. This helps to accommodate both 8-position plugs (in whichcontacts 1 and 8 make electrical connection with corresponding contactsin the plug) and 6-position plugs (in which contacts 1 and 8 are pusheddown by a solid plastic portion that is common on most 6-positionplugs). See FIG. 34 for an illustration of contact 1 or 8 with a6-position plug inserted.

The spring contacts 308 provide an alternative FPC connecting mechanismto that described in other embodiments set forth herein (i.e. welding,etc.). During manufacture (or installation) the FPC 312 may be insertedinto some or all of the spring contacts 318. The spring contacts 318provide a holding force that pinches the FPC to hold it in place toallow a good electrical connection.

The disclosed invention provides an electrical connector employingcrosstalk-reduction techniques. It should be noted that theabove-described and illustrated embodiments and preferred embodiments ofthe invention are not an exhaustive listing of the forms such theinvention might take; rather, they serve as exemplary and illustrativeembodiments of the invention as presently understood. By way of example,and without limitation, the jack 110 of FIGS. 18-22 may be manufacturedwith a forward bend in the FPC 114, similar to the forward bend 34 shownin FIG. 5.

The invention claimed is:
 1. A method of compensating for crosstalk in amodular communication connector comprising a plug and a jack, the jackcomprising a plurality of jack contacts and a plurality of insulationdisplacement connectors (IDCs) configured to connect to wires of acable, each jack contact having an interface at which the plug, wheninserted into the jack, contacts the jack contact, the methodcomprising: connecting a flexible printed circuit (FPC) to the jackcontacts such that a first end of the FPC is connected to each jackcontact approximately adjacent to and on an opposite side from theinterface; and connecting a second end of the FPC to the IDCs, the FPCproviding a network path for at least two conductor pairs between thejack contacts and the IDCs.
 2. The method of claim 1, further comprisingattaching the second end of the FPC to a rigid printed circuit board. 3.The method of claim 1, wherein: the network path comprises conductivetraces that provide crosstalk compensation and include a Near End (NEXT)compensation zone, a Near End (NEXT) crosstalk zone, a first transitionzone between the jack contacts and the NEXT crosstalk zone, and a secondtransition zone between the NEXT compensation zone and the NEXTcrosstalk zone, and at a first frequency the NEXT crosstalk zone has anassociated magnitude of total crosstalk coupling that is approximatelyequal to that of a specification plug and the NEXT compensation zone hasan associated magnitude of total compensation coupling that is slightlyless than twice that of a specification plug plus that of the first andsecond the transition zones.
 4. The method of claim 3, wherein the NEXTcompensation zone, the NEXT crosstalk zone, and the first and secondtransition zones each have distributed couplings and substantially noremote couplings.
 5. The method of claim 4, wherein at a firstfrequency, a first phase angle change between an effective center ofcouplings of an installed specification plug and a center of the NEXTcompensation zone is approximately equal to a second phase angle changebetween a center of the NEXT crosstalk zone and a center of the NEXTcompensation zone.